+-----------+---------------------+-----------------+-------+-------+ | | | | | | | | Non-cross-overs. | Cross-overs. | | | | | | | | Cross-| | Reference.+----------+----------+----------+------+ Total.| over | | | | | | | | value.| | |Miniature |Wild-type.|Miniature.|Sable.| | | | | sable. | | | | | | +-----------+----------+----------+----------+------+-------+-------+ | | | | | | | | | 38 I | 245 | 283 | 15 | 17 | 560 | 6 | | 43 I | 191 | 236 | 13 | 18 | 458 | 7 | | 46 I | 232 | 274 | 24 | 21 | 551 | 8 | | +----------+----------+----------+------+-------+-------+ | Total | 668 | 793 | 52 | 56 | 1,569 | 7 | | | | | | | | | +-----------+----------+----------+----------+------+-------+-------+ Since the results for the male and the female classes are expected to be the same, the sexes were not separated. The combined data give 7 per cent of crossing-over between miniature and sable. LINKAGE OF VERMILION, SABLE, AND BAR. Bar eye has been described by Mrs. S. C. Tice (1914). It is a dominant sex-linked character, whose locus, lying beyond vermilion and sable, is near the right end of the chromosome series, that is, at the end opposite yellow. In the first cross of a balanced series of experiments for the gens vermilion, sable, and bar, vermilion (gray not-bar) entered from one side ([female]) and (red) sable bar from the other ([male]). The daughters were bar and the sons vermilion. The daughters were back-crossed singly to the triple recessive males vermilion sable (not-bar), and gave the data included in table 14. In the second cross, vermilion sable (not-bar) went in from one side ([female]) and (red, gray) bar from the other. The daughters were bar and the sons were vermilion sable. Since these sons have the three recessive factors, inbreeding of F_1 is equivalent to a triple back-cross. The results are given by pairs in table 15. {41} TABLE 14.--_P_1 vermilion [female] [female] x sable bar [male] [male]. B. C. F_1 bar [female] x vermilion sable [male] [male]._